Abstract
A stable neutralino assumed to be the lightest supersymmetric particle, is a favored particle physics candidate for cosmological dark matter. We study coannihilation of the lightest neutralino with the lighter scalar top quark We show that for natural values of the neutralino mass, GeV, the - mass difference has to exceed to 30 GeV if is to contribute significantly to the dark matter. Scenarios with smaller mass splitting, where is quite difficult to detect at collider experiments, are thus cosmologically disfavored. On the other hand, for small - mass splitting, we show that coannihilation allows superparticle masses well beyond the reach of the CERN LHC, TeV, without “overclosing” the Universe.
- Received 29 November 1999
DOI:https://doi.org/10.1103/PhysRevD.62.035012
©2000 American Physical Society